Conus artery occlusion causing isolated right ventricular outflow tract infarction: novel application of cardiac magnetic resonance in anterior STEMI

Abstract

Acute ST elevation in the anterior precordial leads typically suggests an anteroseptal infarction due to left anterior descending coronary artery obstruction, but the differential can be broad. Conus branch artery occlusion is a potentially overlooked cause of anteroseptal ST elevation myocardial infraction. Cardiac magnetic resonance (CMR) imaging is an emerging technology which can differentiate the etiology of anterior ST elevation in patients with no apparent coronary abnormalities on coronary angiography and normal echocardiography.

Keywords: Conus artery; bicuspid aortic valve; magnetic resonance imaging (MRI); myocardial infarction.

Figure 1

Coronal T2 weighted and axial ADC map diffusion weighted images of the brain revealing signal in the inferolateral right temporal lobe, indicative of a chronic middle cerebral artery (MCA) territory infarction.

Figure 2

Parasternal long axis view of the bicuspid aortic valve demonstrating the mobile echo densities.

Figure 3

Electrocardiogram illustrates ST segment elevations in leads V1-V3.

Figure 4

Aortogram used to visualize the right coronary artery (RCA). A conus branch was not visualized on the aortogram or injection of the RCA (not shown).

Figure 5

T2 weighted triple inversion recovery fast spin echo magnetic resonance imaging (MRI) sequence illustrating right ventricular outflow tract (RVOT) myocardial edema.

Figure 6

Still frame from dynamic first pass perfusion imaging (FGRET). Blue arrows highlight lack of perfusion in the right ventricular outflow tract (RVOT).

Figure 7

Late gadolinium enhancement of the right ventricular outflow tract (RVOT). Blue arrows demonstrate subtle enhancement of thin right ventricular (RV) myocardium.